I have been trying to get the dealership to diagnose this same issue for a few months now and after two and a half weeks of diagnosing this is the answer I got from the shop foreman.
Since we chatted we have brought the unit back in. Ford wanted us to remove the spark plugs again, to let the unit sit over night and borescope all the cylinders, and look for oil presence in the cylinder or on the valves as we rotated the engine. We could not find any oil leaking into the cylinders. They asked us if the engine was loosing any oil during services, and it’s not. They also asked us to find several units to compare to each other on start up. Due to the style of engine that your explorer has, it has a direct injection system rather then a port injection. This causes smoking on cold starts, and even with warm start ups, just not as noticeable. We have had 2 other units at work in the last couple of days and we set them all up to cold start them. Each unit had smoke emitting from the exhaust upon cold start. We drove each unit the same way so we could compare them equally on start up. I will attach a video of one of the other units for your reference.
So at this point Ford has said that since we have tested several like units and they all have the same amount of smoke emitting from the exhaust, that this is a normal characteristic for this type of engine. Since it does not run rough, lack power or burn any oil Ford has stated that there is nothing that can been done at this time, and again this is a normal characteristic.
I know this is not the response you were hoping for. If you have further questions please feel free to contact myself, or you can contact Ford Customer relations.
He did send me a video of a different ST and it was belching that exhaust. No other vehicle that I know of does this. In previous emails he said they narrowed this extra exhaust down to the drivers side. So logically it would also do it on the other side if it’s normal and it would do it from day one upon vehicle delivery. So I’m not buying it that this is normal. I have been reading this forum thread and have told them to check out the exhaust side of that turbo and they completely ignore me. I mean it is an exhaust issue so you would go along the exhaust from the back end forward and inspect all the parts along the way. That’s what a guy would logically do. But ford engineers didn’t want to do that. They just wanted to start at the block and do a bunch of useless garbage there and say yup this is normal. The only other thing I can think of is because it’s direct injection and there is oil fuel dilution and somehow that is causing the issue. So I asked for an oil change to see if that would help. As for the other customer STs I don’t know why they don’t see it as an issue. Either they don’t know any better or just don’t care. My friends ‘21 ST doesn’t do it, but if it was normal his would too. I feel like I am being given the runaround and either Ford has no idea what the problem is or they do and they just do not want to repair this item especially seen as how it must affect a lot of vehicles. So I’m just going to give another dealership a shot and pull all my business from the one I was at. Also Ford customer relations told me to F off too. So they are of no help.